package pl.wroc.pwr.mss.server.util;

import java.sql.Types;

import org.hibernate.Hibernate;
import org.hibernate.dialect.Dialect;
import org.hibernate.dialect.function.SQLFunctionTemplate;
import org.hibernate.dialect.function.StandardSQLFunction;
import org.hibernate.dialect.function.VarArgsSQLFunction;

/**
 * Definicja dialektu SQL'owego dla systemy SQLite.
 *
 * @author mjagus
 */
public class SQLiteDialect extends Dialect
{
    /**
     * Iniciuje dialekt.
     */
    public SQLiteDialect()
    {
        super();
        registerColumnType(Types.BIT, "integer");
        registerColumnType(Types.TINYINT, "tinyint");
        registerColumnType(Types.SMALLINT, "smallint");
        registerColumnType(Types.INTEGER, "integer");
        registerColumnType(Types.BIGINT, "bigint");
        registerColumnType(Types.FLOAT, "float");
        registerColumnType(Types.REAL, "real");
        registerColumnType(Types.DOUBLE, "double");
        registerColumnType(Types.NUMERIC, "numeric");
        registerColumnType(Types.DECIMAL, "decimal");
        registerColumnType(Types.CHAR, "char");
        registerColumnType(Types.VARCHAR, "varchar");
        registerColumnType(Types.LONGVARCHAR, "longvarchar");
        registerColumnType(Types.DATE, "date");
        registerColumnType(Types.TIME, "time");
        registerColumnType(Types.TIMESTAMP, "timestamp");
        registerColumnType(Types.BINARY, "blob");
        registerColumnType(Types.VARBINARY, "blob");
        registerColumnType(Types.LONGVARBINARY, "blob");
        // registerColumnType(Types.NULL, "null");
        registerColumnType(Types.BLOB, "blob");
        registerColumnType(Types.CLOB, "clob");
        registerColumnType(Types.BOOLEAN, "integer");

        registerFunction("concat", new VarArgsSQLFunction(Hibernate.STRING, "",
                "||", ""));
        registerFunction("mod", new SQLFunctionTemplate(Hibernate.INTEGER,
        "?1 % ?2"));
        registerFunction("substr", new StandardSQLFunction("substr",
                Hibernate.STRING));
        registerFunction("substring", new StandardSQLFunction("substr",
                Hibernate.STRING));
    }

    @Override
    public boolean supportsIdentityColumns()
    {
        return true;
    }

    @Override
    public boolean hasDataTypeInIdentityColumn()
    {
        return false; // As specify in NHibernate dialect
    }

    @Override
    public String getIdentityColumnString()
    {
        // return "integer primary key autoincrement";
        return "integer";
    }

    @Override
    public String getIdentitySelectString()
    {
        return "select last_insert_rowid()";
    }

    @Override
    public boolean supportsLimit()
    {
        return true;
    }

    @Override
    public String getLimitString(String query, boolean hasOffset)
    {
        return new StringBuffer(query.length() + 20).append(query).append(
                hasOffset ? " limit ? offset ?" : " limit ?").toString();
    }

    @Override
    public boolean supportsTemporaryTables()
    {
        return true;
    }

    @Override
    public String getCreateTemporaryTableString()
    {
        return "create temporary table if not exists";
    }

    @Override
    public boolean dropTemporaryTableAfterUse()
    {
        return false;
    }

    @Override
    public boolean supportsCurrentTimestampSelection()
    {
        return true;
    }

    @Override
    public boolean isCurrentTimestampSelectStringCallable()
    {
        return false;
    }

    @Override
    public String getCurrentTimestampSelectString()
    {
        return "select current_timestamp";
    }

    @Override
    public boolean supportsUnionAll()
    {
        return true;
    }

    @Override
    public boolean hasAlterTable()
    {
        return false; // As specify in NHibernate dialect
    }

    @Override
    public boolean dropConstraints()
    {
        return false;
    }

    @Override
    public String getAddColumnString()
    {
        return "add column";
    }

    @Override
    public String getForUpdateString()
    {
        return "";
    }

    @Override
    public boolean supportsOuterJoinForUpdate()
    {
        return false;
    }

    @Override
    public String getDropForeignKeyString()
    {
        throw new UnsupportedOperationException(
        "No drop foreign key syntax supported by SQLiteDialect");
    }

    @Override
    public String getAddForeignKeyConstraintString(String constraintName,
            String[] foreignKey, String referencedTable, String[] primaryKey,
            boolean referencesPrimaryKey)
    {
        throw new UnsupportedOperationException(
        "No add foreign key syntax supported by SQLiteDialect");
    }

    @Override
    public String getAddPrimaryKeyConstraintString(String constraintName)
    {
        throw new UnsupportedOperationException(
        "No add primary key syntax supported by SQLiteDialect");
    }

    @Override
    public boolean supportsIfExistsBeforeTableName()
    {
        return true;
    }

    @Override
    public boolean supportsCascadeDelete()
    {
        return false;
    }
}